How can I create time in proper format to export to a netCDF (.nc) file in MATLAB?

Data

I am trying to create a time dimension using this

'''

t1 = datetime(1901,1,1);

t2 = datetime(2016,12,31);

t = t1:t2;

'''

And create a netCDF file using this

'''

nccreate('prec.nc','Prec',...

'Dimensions',{'time' 42369 'lon' 135 'lat' 129},...

'Format', 'netcdf4');

'''

What I have tried

ncwrite('prec.nc', 'time', t);

Error Message

Error using cast

Unsupported data type for conversion: 'datetime'.

Error in internal.matlab.imagesci.nc/write (line 778)

scale_factor = cast(1, class(varData));

Error in ncwrite (line 87)

ncObj.write(varName, varData, start, stride);

Question

How can I create a daily time dimension that I can write out to a netCDF file? What is the proper date type for this conversion?

Answer 1

[KSSV]

Convert the dates into numbers using datenum. These numbers can be written into netCDF file. Read about datenum.

[Ravi Raj]

#Used Command

n1 = datenum(1901,1,1);

n2 = datenum(2016,12,31);

ncwrite('precip_IMD.nc', 'time', n1:1:n2);

#It is exported in netcdf file but the date gets started from 3802-01-02 instead of 1901-01-01 .

I have attached the exported date plot file also. Please have a look and guide me.

[KSSV]

t1 = datetime(1901,1,1);
t2 = datetime(2016,12,31);
t = t1:t2;
t = datenum(t) ; 

YOu check the conversion in MATLAB itself before writitng to nc. Convert datetime to datenum and vice versa..once it is confirmed..then write to .nc

[Ravi Raj]

I have converted datenum into datetime and vice-versa. You can see in following commands:

TRIED

>> t1 = datenum(1901,1,1)

t1 =

694327

>> t2 = datenum(2016,12,31)

t2 =

736695

>> x1 = datetime(t1,'ConvertFrom','datenum')

x1 =

datetime

01-Jan-1901 00:00:00

>> x2 = datetime(t2,'ConvertFrom','datenum')

x2 =

datetime

31-Dec-2016 00:00:00

BUT

While writting into nc format the datenum 694327 is returning as 3802-01-02 and 736695 as 3918-01-02 instead of returning as (1901,1,1) and (2016,12,31) respectively.

I am attaching here the screenshot of returning value in nc format. Please have a look.